I'm not going to win any popularity contests here but I don't think either of them are particularly floyd-like - TFC is the third Waters solo album (after Animals and The Wall) and TDB, like AMLOR, is simply the embarrassing sound of a bunch of cash-fixated old duffers going through their respective midlife crises. It sounds to me that with both Signs of Life and Keep Talking Dave simply thought 'It sounds a bit like Shine On - should sell...'
IMHO Pink Floyd haven't really sounded like Pink Floyd on an entire album since DSOTM. To paraphrase Dave Gilmour on Classic Albums the bands goal was to be successful and make a lot of money and I believe the subsequent albums suffered as a result. WYWH has two genuinely great songs on (Shine On and the title track) but I feel that HAC and WTTM were the beginning of Waters' domination of the band.
Finally, I'd like to say that subsequent albums aren't without merit (Animals is fantastic, but more a Waters solo album)
but for me the joy of Pink Floyd's music seem to be confined to the first eight albums.